The key to retain your customers happy is to find out what precisely motivates them, what is most important to them and what they want most. Then, find the product that gives them what they want at the best value.
Customers will not tell you straight how they felt about your product. But when an independent third party asks them for their feedback they don't hesitate to react. If you really want to know the customers' mind, engage a professional consultant or a telemarketing company to conduct customer satisfaction surveys.
Sales people often take action depending on what they think important rather than what is pertinent to their clients. You must ask your clients about their real needs. This will help you know which product feature has to be focused. Discuss the benefits and the problems your product can solve. This type of approach will lead you to the possible problems they are facing with your product and you can find a way to satisfy them.
An important thing you must remember is that a sales person should be a good listener too.
You must ask your customers what they want through specific questions. Don't make any non-specific questions. If they are confused and don't know what they want, ask them what they don't want.
When you are dealing with client companies, your main aim should be to know your good customers and to serve them well. In other words, you must know how to satisfy your customers. In this direction, it is essential for you to know how they operate and who makes their decisions.
You can get this information by writing up detailed account plans for your most profitable accounts. These should reflect your position vis-a-vis the client's industry and revenue projections. You should also know the impending threats to your position with respect to your client. You must plan to expand and maintain your relationship with your client company.